CODEWITHSUNDEEP
c++matlab
physicsGuy
physicsGuy

Reputation: 3675

C++ and Matlab combination

I am writing a simulation of some differential equation. My idea was the following:

1. Write the core simulation (moving forward in time, takes a lot of time) in C++
2. Do initialisation and the analysis of the results with a program
   like Matlab/Scilab

The reason for (1) is that C++ is faster if implemented correctly.

The reason for (2) is that for me it is easier to make analysis, like plotting etc..., with a program like Matlab.

Is it possible to do it like this, how do I call C++ from Matlab? Or do you have some suggestions to do it in a different way?

Upvotes: 2

Views: 254

Answers (3)

Plo_Koon
Plo_Koon

Reputation: 3033

You can call your own C, C++, or Fortran subroutines from the MATLAB command line as if they were built-in functions. These programs, called binary MEX-files, are dynamically-linked subroutines that the MATLAB interpreter loads and executes. You should set compiler, look here Setting up mex to use the Visual Studio 2010 compiler. All about MEX-files here: http://www.mathworks.com/help/matlab/matlab_external/using-mex-files-to-call-c-c-and-fortran-programs.html.

Upvotes: 1

sbabbi
sbabbi

Reputation: 11181

Yes, Matlab has a C/C++ API.

This API permits to:

  • Write C++ functions which can be invoked from Matlab
  • Read/Write data from a .mat file
  • Invoke the Matlab engine from C++

I am working to something similar to what you are trying to do, my approach is:

  • Import in C++ the input data from a .mat file
  • Run the simulation
  • Export the results back in a .mat file

The Matlab API is in C, and I suggest you to write a C++ wrapper for your convenience.

In order to work with Matlab mxArray, I suggest to take a look at the boost::multi_array library.

In particular you can initialize an object of type multi_array_ref from a Matlab mxArray like this:

boost::multi_array_ref<double,2> vec ( mxGetPr (p), boost::extents[10][10], boost::fortran_storage_order() );

This approach made the code much more readable.

Upvotes: 3

High Performance Mark
High Performance Mark

Reputation: 78306

You could certainly do as you suggest. But I suggest instead that you start by developing your entire solution in Matlab and only then, if its performance is genuinely holding your work back, consider translating key elements into C++. This will optimise the use of your time, possibly at the cost of your computer's time. But a computer is a modern donkey without a humane society to intervene when you flog it to death.

As you suggest, well written C++ can be expected to be faster than interpreted Matlab. But ask yourself What is Matlab written in ? For much of its computationally-intensive core functionality Matlab calls libraries written in C++ (or whatever). Your task would be not to write code faster than interpreted Matlab, but faster than C++ (or whatever) written by specialists urged on by a huge market of installed software.

Upvotes: 4

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